6-fluoro-3, 11-diketo-delta4, 17(20)-pregnadien-21-oic acid esters



Patented Dec. 17, 1%63 their production can be illustrated by the following re- 3,114,757 action scheme. 6-FLUORG 3JI-DMETO-A -PREGNADEEN- ll-OTC ACED ESTERS Robert W. Jackson and Sohn E. Pike, Kalamazoo, Mich, 5 OR 0 O R assignors to The Upjohn Qompany, Katamazoo, Mich, C a corporation of Delaware OH CH N0 Drawing. Filed Sept. 22, 1961, S-er. No. 139,838 H H 2 Claims. oi. zoo-3am /\i 2p This invention relates to certain novel 6-fluoro steroids, CH3 CH3 more particularly to G-fluoro \Favorskii esters of the formula:

002R Z I F @111 wherein R is hydrocarbon, preferably lower-hydrocarbon, e.g., methyl, ethyl, benzyl, etc. and R has the meaning 011 i previously given, namely, lower alkyl, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, hexyl, oxtyl, etc. The starting steroids for the process of this invention 1 are 3-alkoxy 11 keto-3,5,l7(2())-[cis]-pregnatrien-2l- 2 oic acid alkyl esters, e.g., 3-ethoxy-l1-keto-3,5,l7(20)- F [cis]-pregnatrien-21-oic acid methyl ester and S-alkoxy- 'll-keto-3,5,17(20)-[trans]-pregnatrien-21-oic acid alkyl wherein R is an alkyl group containing from 1 to 8 cari i 3'lpethoxy'l1'ketO 3517(20)'[trans]? mgna hm atoms inclusive tr1en--1-o1e acid methyl ester.

In this application the wavy line (I) represents a gen- In carrymg out the process of this mvsnnoil the lected 3-alkoxy l1 keto-3,5,17(20)-pregnatrien-2l-o1c eric expression including the alpha (u) and beta (,6) con- 1k ,1 t 3 th 11 1, to 3 5 17(20) figuration and/or mixtures thereof; and unless specifically am a 6S i as] designated as cis or trans, the configuration of the 21- pregnamena acid methyl ester 18 leaded Wlth hloryl fluoride in the presence of a tertiary amine to obcarboxyl group attached to the double bonded C20 car- 1 bon includes both the cis and trans configuration and/or l 6 flu0m'4.17(20)'pr(?gnad1en'21' mixtures thereof 01C acid alkyl ester, e.g., 3,11-d1. eto-6-fluoio-4,l7(20)- pregnadien-Zl-oic acid methyl ester. The starting steroid l of Formula I, are useful intermediates in the preparation ff 'figg fg i, ZZ3 g -Z Z EQZ S61623 2122: as ril v Iv Cl .1 i \1 v 25 ggf g'f fi ig giggq gi z g gif :33 & 40 reaction solvent. However, other inert organic solvents, acylates thereof y j e.g., diethyl ether, benzene, toluene, methanol, ethanol, In addition i com Ounds of Formula I 0 S a chloroform, carbon tetrachloride, dimethylsulfoxide, div s 635 n oxane, tetrahydrofuran, etc., can be employed as a diluent mflammatory, glucocorucoid, mineralocorticoid, progestaor Solvent flonal andmgemc i and Centr Ordinarily it is preferred not to have a laree excess of vous system regulating properties. Furthermore, the comperchloryl fliioride in the reaction mixture a t least dur- F of pdormula when adfmlmstered m the presence ing the beginning of the reaction. Therefore, perchloryl Q i an testosferone of potent estrogens fluoride is preferably bubbled into the solution of the e.g., es rone, o potent progestms e.g. progesterone and steroid. Alternativel 1t can be added as a solution m off pgtent salt retainers, e.g., desoxycortlcosterone, mhibit a Suitable inert solvegt' The amount of prchloryl 25 1 225 32? gzi i g i zzg g ii g i. t ride employed in the reaction depends in part upon the of Th t t d 0 d h aOWIPY reaction temperature and the selected stanting steroid. Opisf en means an t us exhlblt antlandrogemc timum yields of desired product are ordinarily achieved 1, ernloin atlast mo e' e i Administration of the novel steroids of Formula I a i on g g g g i of p rchloryl flue can be In conventlonal forms Such as l P' As is apparent to those skilled in the art, the tertiary 2 g Syrups or ehxlrs for Oral or m hqmd amine employed in the process of this invention s ould orrtriis lw lCh areh adaptable to the natural and synthetl be substantially non-reactive toward the perchloryl fluof gg i gg g gi i i g i 1 The ride. The amines preferred for their non-reactivity are topically in the form 3% 3 g riumstered the hydrocarbon tertiary amines, either aromatic or alithe like with or Without 6 it Pr phatic, e.g., trialkylamines, triethylamine, tributylamine, h 1 mg an 1 N-methylpiperidine and aralkylamines, e.g., benzyldies 0t matena S formmg advantageous combma' methylamine dibenzylmethylamine tribenzylamine Es 10118 t erewi pecially preferred are the aromatic tertiary-N-heterocyclic MOI-Fever the ,compounds of Formula 1 f useful amines. These amines are characterized by their amino ultra-violet screening agents. When used topically they nitrogen a a member of a group which absorb Pomon of the {Tythema R Oducmg ultra-Violet is part of an aromatic ring, and include the pyridines, e.g. r i g d lhe Same tlme Perm1t thahtamllng i pyridine, picoline, :xand B-lutidine, oc-, 8- and 'y-collidine, V10 5t an 5 t0 cflme thTOUg1 1- Thus, y are useflll propylpyridine, the parvolines, and quinoline, isoquinoultra-violet screening agents in the tanning of human line, pyridopyridine, napthyridine, etc. While any of SklIl. these and like aromatic tertiary-N-heterocyclic amines can The novel compounds of Formula I and a process for be used in the process of this invention, it is preferred to The novel compounds of this invention, the compounds use the pyridine series, i.e., pyridine and its homologues, with pyridine being the amine of choice. At least a molar equivalent of amine, calculated on the perchloryl fiuoride, is preferably employed, with a very large excess of the amine being ordinarily desirable, e.g., using the amine as a reaction solvent.

The reaction temperature can be varied considerably, e.g., from 75 to +100 C. without affecting the operability of the process. Generally, a temperature range of from -40 to +40 C. is preferred. For convenience, room temperature is often the desired reaction temperature, although somewhat lower temperatures sometimes give higher yields of the desired product.

3-enol ethers are Well known in the art and may be readily prepared from the corresponding A -3-keto steroid in a number of ways, e.g., by reaction of the A -3-keto steroid with a lower-allryl orthoformate in the presence of an acid catalyst, e.g., p-toluenesulfonic acid, sulfuric acid or methanesulfonic acid. See, e.g., Serini and Koster, Berichte, 71: 1766 (1938) and British Patent 737,773. The enol etherification can be conducted under conditions which will produce selectivity. Thus, the A -3-keto group can be enol etherified without affecting the ll-keto group, ordinarily by merely running the etherification under mild conditions, e.g., as shown in the preparations hereinafter. The 3-ether radical is preferably hydrocarbon, e.g., lower-hydrocarbon, e.g., benzyl, p-methylbenzyl, lower-aliphatic, lower-alkyl, e.g. methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, and octyl.

The 3,1l-diketo 6 fiuoro-4,17(20)-pregnadien-2l-oicacid alkyl ester, e.g., 3,1l-diketo-6-fiuoro-4,l7(20)-[cis]- pregnadien-21-oic acid methyl ester, produced by the process of this invention can be isolated in the usual fashion, e.g., removing the reaction solvent and fractionally crystallizing, chromatographing, counter-currently extracting, or a combination of these procedures.

The process of this invention provides both 604- and fifl-fluoro steroids. As is known in the art, 6B-fluoro-A 3-keto steroids can be converted to 6zx-fluoro-A -3-keto steroids by bubbling anhydrous hydrogen chloride into a solution of the steroid in chloroform containing ethanol at about C.

The following preparations and examples are illustrative of the process and products of the present invention.

PREPARATION 1 3-Eth0xy-11-Kct0-3,5,1 7(20)- [Cis] -Pregnatrien- ZI-Oic Acid Methyl Ester A mixture of 10.0 g. of 3,11-diketo-4,l7(20)-[cis]- pregnadien-Zl-oic acid methyl ester, 1.0 g. of p-toluenesulfonic acid monohydrate and 100 ml. of ethyl orthoformate was heated under reflux for one hour and then evaporated to dryness at reduced pressure. The semicrystalline residue was recrystallized from a mixture of methanol and pyridine to give 8.1 g. of 3-ethoXy-11-keto- 3,5,17(20)-[cis]-pregnatrien-21-oic acid methyl ester melting at 146-149 C.

Similarly, following the above procedure, but substituting the ethyl, propyl, butyl or octyl ester of 3,11-diketo-4,17(20)-[cis] -preguadien-21-oic acid or 3,11-diketo- 4,17(20)-[trans]-pregnadien-2l-oic acid as the starting steroid, there is thus produced the ethyl, propyl, butyl and octyl ester of 3-ethoxy-11-keto-3,5,17(20)-[cis]-pregnatrien-21-oic acid or 3-ethoxy-11-keto-3,5,17(20)-[trans]- pregnatrien-Zl-oic acid.

Substituting propyl orthoformate for the ethyl orthoformate in the above reaction is productive of 3-propoxy- 11-keto-3,5,17(20)-[cis]-pregnatrien 21 oic acid methyl ester.

In like manner, substituting propyl orthoformate for ethyl orthoformate in the above reaction and using 3,11- diketo-4,17(20)-[trans]-pregnadien 21 oic acid methyl ester as the starting steroid is productive of 3-propoxy-l1- keto-3,5,17(20)-[trans]-pregnatrien 21 oic acid methyl ester.

PREPARATION 2 To a slurry of 54 g. of finely ground 3,1l-diketo-4, l7(20)-[cis]-pregnadien-21-oic acid methyl ester in 325 ml. of absolute methanol and 75 ml. of methyl orthoformate was added with stirring 30 drops of concentrated sulfuric acid. The reaction product began to precipitate before all the starting material had dissolved. The mixture was stirred at room temperature for about 30 minutes, chilled for about 2.5 hours and the precipitate then separated and washed well with cold methanol to give 483 g. of 3-methoxyll keto-3,5,17(20)-[cis]-pregnatrien-21-oic acid methyl ester, M.P. 179-183" 0.,

A532? 235 m a =27,075 and having the correct elemental analysis.

Similarly, following the above procedure, but substituting 3,11-diketo-4,l7(20)-[trans]-pregnadien-21-oic acid methyl ester for 3,11-diketo-4,17(20)-[cis]-pregnadien- 21-oic acid methyl ester is productive of 3-methoxy-l1- keto-3,5,17(20)-[trans]-pregnatrien 21 oic acid methyl ester.

EXAMPLE 1 3,1I-Diket0-6-Fluor0-4,17(20) [Cis] -Pregnadien- ZJ-Oic Acid Ester Perchloryl fluoride was slowly bubbled into a solution of 4.0 g. of S-ethoxy- 11-keto-3,5,17(20)-[cis]-pregnatrien-Zl-oic acid methyl ester in 200 ml. of pyridine at 0 to 5 C. for 5 minutes. The reaction mixture was then distilled to about half its original volume at reduced pressure and then poured onto ice and dilute hydrochloric acid. The resulting mixture was extracted with ether and the combined ether extracts were washed with aqueous sodium bicarbonate, dried and the residue dissolved in methylene chloride which was then chromatographed on 150 g. of magnesium silicate. The column Wsa developed with -ml. portions of solvent of the following composition and order: 10 of hexanes plus 15% acetone and 10 of hexanes plus 20% acetone. Fractions 8 to 11 eluted 3,11-diketo-6a-fluoro 4,17(20) [cisJ-pregnadien-2l-oic acid methyl ester which was recrystallized from methanol to give 250 mg. of crystals melting at 224226 C. (dec.). A second recrystallization from methanol raised the melting point to 226-228 C. (dec.). These crystals had the correct elemental analysis,

W011 229 m a 27,900; D +17s max.

A1523? 227 m a 23,100; [011 +88 EXAMPLE 2 3,]1-Diket0-6-Fluor0-4,17(20)- Trans] -Pregnadien- ZZ-Oz'c Acid Methyl Ester Perchloryl fluoride is slowly bubbled into a solution of 2.0 g. of 3-rnethoxy-11-keto-3,5,17(20)-[trans]-pregnatrien-21-oic acid methyl ester in 100 ml. of pyridine at 0 to 5 C. for 5 minutes. The reaction mixture is distilled in vacuo to about half its original volume and then poured onto ice and dilute hydrochloric acid. The resulting mixture is extracted with ether and the combined ether extracts are Washed with aqueous sodium bicarbonate, dried, evaporated to dryness in vacuo, taken up in methylene chloride (25 ml.) and poured onto a chromatographic column containing 100 g. of magnesium silicate. The chromatographic column is developed by eluting with hexanes containing increasing proportions of acetone. The eluate fractions are freed of solvent and those early fractions having an ultraviolet absorption near 229 m are combined to give 3,11-diketo-6a-fluoro-4,17(20)-[trans]- pregnadien-2l-oic acid methyl ester. Those later fractions having an ultraviolet absorption near 227m are combined to give 3,11-diket0-6fi-luoro-4J7(20)-[trans]- pregnadien-Zl-oic acid methyl ester.

In like manner, following the above procedure, but substituting other 3-alkoxy-11-l;eto-3,5,17(20)-[cis]-pregnatrien-Zl-oic acid alkyl esters and 3-alkoXy-11-keto-3,5, 17(20)-[trans]-pregnatrien-21-oic acid alkyl esters, e.g., S-ethoxy 11 keto-3,5,17(20)-[trans]-pregnatrien-21- oic acid methyl ester, 3-methoxy-11-keto-3,5,17(20)-[cis]- pregnatrien-Zl-oic acid methyl ester, 3-propoxy-11-keto- 3,5,17(20)-[cis]-pregnatrien-21-oic acid methyl ester, 3- propoxy-i1-keto-3,5,17(20) [trans] pregnatrien-21-oic acid methyl ester, and the ethyl, propyl, butyl and octyl esters of S-ethoxy-ll-keto-3,5,17(20)-[cis]-pregnatrien- 21-oic acid and 3-ethoxy-11-keto-3,5,17(20)-[trans]-pregnatrien-2l-oic acid, as the starting steroid for S-methoxy- 1l-keto-3,5,l7(20)-[trans]-pregnatrien-21-oic acid methyl ester, there is thus produced the corresponding 3,11-diket0-6-fluoro-4,l7(20)-[cis]-pregnadien-21-oic acid alkyl esters and 3,11-diketo-6-fluoro-4,17(20)-[trans]-pregna- 6 dien-2l-oic acid alkyl esters, e.g., the 60:- and 6,8-epirners of 3,11 diketo-6-fiuoro-4,17(20)[cis]-pregnadien-21-oic acid methyl ester, 3,11-dike'to-6-flnoro-4,17(20)-[trans]- pregnadien-Zl-oic acid methyl ester, and the ethyl, propyl, butyl and octyl esters of 3,11-diketo-6-fiuoro-4,l'7(20)- 

1. 3,11-DIKETO-6A-FLUORO-4,17(20) - (CIS) - PREGNADIEN21-OIC ACID METHYL ESTER. 